bpo-31333: Re-implement ABCMeta in C (#5273)
This adds C versions of methods used by ABCMeta that
improve performance of various ABC operations.
diff --git a/Lib/_py_abc.py b/Lib/_py_abc.py
new file mode 100644
index 0000000..6f42ef3
--- /dev/null
+++ b/Lib/_py_abc.py
@@ -0,0 +1,145 @@
+from _weakrefset import WeakSet
+
+
+def get_cache_token():
+ """Returns the current ABC cache token.
+
+ The token is an opaque object (supporting equality testing) identifying the
+ current version of the ABC cache for virtual subclasses. The token changes
+ with every call to ``register()`` on any ABC.
+ """
+ return ABCMeta._abc_invalidation_counter
+
+
+class ABCMeta(type):
+ """Metaclass for defining Abstract Base Classes (ABCs).
+
+ Use this metaclass to create an ABC. An ABC can be subclassed
+ directly, and then acts as a mix-in class. You can also register
+ unrelated concrete classes (even built-in classes) and unrelated
+ ABCs as 'virtual subclasses' -- these and their descendants will
+ be considered subclasses of the registering ABC by the built-in
+ issubclass() function, but the registering ABC won't show up in
+ their MRO (Method Resolution Order) nor will method
+ implementations defined by the registering ABC be callable (not
+ even via super()).
+ """
+
+ # A global counter that is incremented each time a class is
+ # registered as a virtual subclass of anything. It forces the
+ # negative cache to be cleared before its next use.
+ # Note: this counter is private. Use `abc.get_cache_token()` for
+ # external code.
+ _abc_invalidation_counter = 0
+
+ def __new__(mcls, name, bases, namespace, **kwargs):
+ cls = super().__new__(mcls, name, bases, namespace, **kwargs)
+ # Compute set of abstract method names
+ abstracts = {name
+ for name, value in namespace.items()
+ if getattr(value, "__isabstractmethod__", False)}
+ for base in bases:
+ for name in getattr(base, "__abstractmethods__", set()):
+ value = getattr(cls, name, None)
+ if getattr(value, "__isabstractmethod__", False):
+ abstracts.add(name)
+ cls.__abstractmethods__ = frozenset(abstracts)
+ # Set up inheritance registry
+ cls._abc_registry = WeakSet()
+ cls._abc_cache = WeakSet()
+ cls._abc_negative_cache = WeakSet()
+ cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
+ return cls
+
+ def register(cls, subclass):
+ """Register a virtual subclass of an ABC.
+
+ Returns the subclass, to allow usage as a class decorator.
+ """
+ if not isinstance(subclass, type):
+ raise TypeError("Can only register classes")
+ if issubclass(subclass, cls):
+ return subclass # Already a subclass
+ # Subtle: test for cycles *after* testing for "already a subclass";
+ # this means we allow X.register(X) and interpret it as a no-op.
+ if issubclass(cls, subclass):
+ # This would create a cycle, which is bad for the algorithm below
+ raise RuntimeError("Refusing to create an inheritance cycle")
+ cls._abc_registry.add(subclass)
+ ABCMeta._abc_invalidation_counter += 1 # Invalidate negative cache
+ return subclass
+
+ def _dump_registry(cls, file=None):
+ """Debug helper to print the ABC registry."""
+ print(f"Class: {cls.__module__}.{cls.__qualname__}", file=file)
+ print(f"Inv. counter: {get_cache_token()}", file=file)
+ for name in cls.__dict__:
+ if name.startswith("_abc_"):
+ value = getattr(cls, name)
+ if isinstance(value, WeakSet):
+ value = set(value)
+ print(f"{name}: {value!r}", file=file)
+
+ def _abc_registry_clear(cls):
+ """Clear the registry (for debugging or testing)."""
+ cls._abc_registry.clear()
+
+ def _abc_caches_clear(cls):
+ """Clear the caches (for debugging or testing)."""
+ cls._abc_cache.clear()
+ cls._abc_negative_cache.clear()
+
+ def __instancecheck__(cls, instance):
+ """Override for isinstance(instance, cls)."""
+ # Inline the cache checking
+ subclass = instance.__class__
+ if subclass in cls._abc_cache:
+ return True
+ subtype = type(instance)
+ if subtype is subclass:
+ if (cls._abc_negative_cache_version ==
+ ABCMeta._abc_invalidation_counter and
+ subclass in cls._abc_negative_cache):
+ return False
+ # Fall back to the subclass check.
+ return cls.__subclasscheck__(subclass)
+ return any(cls.__subclasscheck__(c) for c in (subclass, subtype))
+
+ def __subclasscheck__(cls, subclass):
+ """Override for issubclass(subclass, cls)."""
+ # Check cache
+ if subclass in cls._abc_cache:
+ return True
+ # Check negative cache; may have to invalidate
+ if cls._abc_negative_cache_version < ABCMeta._abc_invalidation_counter:
+ # Invalidate the negative cache
+ cls._abc_negative_cache = WeakSet()
+ cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
+ elif subclass in cls._abc_negative_cache:
+ return False
+ # Check the subclass hook
+ ok = cls.__subclasshook__(subclass)
+ if ok is not NotImplemented:
+ assert isinstance(ok, bool)
+ if ok:
+ cls._abc_cache.add(subclass)
+ else:
+ cls._abc_negative_cache.add(subclass)
+ return ok
+ # Check if it's a direct subclass
+ if cls in getattr(subclass, '__mro__', ()):
+ cls._abc_cache.add(subclass)
+ return True
+ # Check if it's a subclass of a registered class (recursive)
+ for rcls in cls._abc_registry:
+ if issubclass(subclass, rcls):
+ cls._abc_cache.add(subclass)
+ return True
+ # Check if it's a subclass of a subclass (recursive)
+ for scls in cls.__subclasses__():
+ if issubclass(subclass, scls):
+ cls._abc_cache.add(subclass)
+ return True
+ # No dice; update negative cache
+ cls._abc_negative_cache.add(subclass)
+ return False
diff --git a/Lib/abc.py b/Lib/abc.py
index 9bdc36d..7094141 100644
--- a/Lib/abc.py
+++ b/Lib/abc.py
@@ -3,8 +3,6 @@
"""Abstract Base Classes (ABCs) according to PEP 3119."""
-from _weakrefset import WeakSet
-
def abstractmethod(funcobj):
"""A decorator indicating abstract methods.
@@ -27,8 +25,7 @@
class abstractclassmethod(classmethod):
- """
- A decorator indicating abstract classmethods.
+ """A decorator indicating abstract classmethods.
Similar to abstractmethod.
@@ -51,8 +48,7 @@
class abstractstaticmethod(staticmethod):
- """
- A decorator indicating abstract staticmethods.
+ """A decorator indicating abstract staticmethods.
Similar to abstractmethod.
@@ -75,8 +71,7 @@
class abstractproperty(property):
- """
- A decorator indicating abstract properties.
+ """A decorator indicating abstract properties.
Requires that the metaclass is ABCMeta or derived from it. A
class that has a metaclass derived from ABCMeta cannot be
@@ -106,131 +101,66 @@
__isabstractmethod__ = True
-class ABCMeta(type):
+try:
+ from _abc import (get_cache_token, _abc_init, _abc_register,
+ _abc_instancecheck, _abc_subclasscheck, _get_dump,
+ _reset_registry, _reset_caches)
+except ImportError:
+ from _py_abc import ABCMeta, get_cache_token
+ ABCMeta.__module__ = 'abc'
+else:
+ class ABCMeta(type):
+ """Metaclass for defining Abstract Base Classes (ABCs).
- """Metaclass for defining Abstract Base Classes (ABCs).
-
- Use this metaclass to create an ABC. An ABC can be subclassed
- directly, and then acts as a mix-in class. You can also register
- unrelated concrete classes (even built-in classes) and unrelated
- ABCs as 'virtual subclasses' -- these and their descendants will
- be considered subclasses of the registering ABC by the built-in
- issubclass() function, but the registering ABC won't show up in
- their MRO (Method Resolution Order) nor will method
- implementations defined by the registering ABC be callable (not
- even via super()).
-
- """
-
- # A global counter that is incremented each time a class is
- # registered as a virtual subclass of anything. It forces the
- # negative cache to be cleared before its next use.
- # Note: this counter is private. Use `abc.get_cache_token()` for
- # external code.
- _abc_invalidation_counter = 0
-
- def __new__(mcls, name, bases, namespace, **kwargs):
- cls = super().__new__(mcls, name, bases, namespace, **kwargs)
- # Compute set of abstract method names
- abstracts = {name
- for name, value in namespace.items()
- if getattr(value, "__isabstractmethod__", False)}
- for base in bases:
- for name in getattr(base, "__abstractmethods__", set()):
- value = getattr(cls, name, None)
- if getattr(value, "__isabstractmethod__", False):
- abstracts.add(name)
- cls.__abstractmethods__ = frozenset(abstracts)
- # Set up inheritance registry
- cls._abc_registry = WeakSet()
- cls._abc_cache = WeakSet()
- cls._abc_negative_cache = WeakSet()
- cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
- return cls
-
- def register(cls, subclass):
- """Register a virtual subclass of an ABC.
-
- Returns the subclass, to allow usage as a class decorator.
+ Use this metaclass to create an ABC. An ABC can be subclassed
+ directly, and then acts as a mix-in class. You can also register
+ unrelated concrete classes (even built-in classes) and unrelated
+ ABCs as 'virtual subclasses' -- these and their descendants will
+ be considered subclasses of the registering ABC by the built-in
+ issubclass() function, but the registering ABC won't show up in
+ their MRO (Method Resolution Order) nor will method
+ implementations defined by the registering ABC be callable (not
+ even via super()).
"""
- if not isinstance(subclass, type):
- raise TypeError("Can only register classes")
- if issubclass(subclass, cls):
- return subclass # Already a subclass
- # Subtle: test for cycles *after* testing for "already a subclass";
- # this means we allow X.register(X) and interpret it as a no-op.
- if issubclass(cls, subclass):
- # This would create a cycle, which is bad for the algorithm below
- raise RuntimeError("Refusing to create an inheritance cycle")
- cls._abc_registry.add(subclass)
- ABCMeta._abc_invalidation_counter += 1 # Invalidate negative cache
- return subclass
+ def __new__(mcls, name, bases, namespace, **kwargs):
+ cls = super().__new__(mcls, name, bases, namespace, **kwargs)
+ _abc_init(cls)
+ return cls
- def _dump_registry(cls, file=None):
- """Debug helper to print the ABC registry."""
- print("Class: %s.%s" % (cls.__module__, cls.__qualname__), file=file)
- print("Inv.counter: %s" % ABCMeta._abc_invalidation_counter, file=file)
- for name in cls.__dict__:
- if name.startswith("_abc_"):
- value = getattr(cls, name)
- if isinstance(value, WeakSet):
- value = set(value)
- print("%s: %r" % (name, value), file=file)
+ def register(cls, subclass):
+ """Register a virtual subclass of an ABC.
- def __instancecheck__(cls, instance):
- """Override for isinstance(instance, cls)."""
- # Inline the cache checking
- subclass = instance.__class__
- if subclass in cls._abc_cache:
- return True
- subtype = type(instance)
- if subtype is subclass:
- if (cls._abc_negative_cache_version ==
- ABCMeta._abc_invalidation_counter and
- subclass in cls._abc_negative_cache):
- return False
- # Fall back to the subclass check.
- return cls.__subclasscheck__(subclass)
- return any(cls.__subclasscheck__(c) for c in {subclass, subtype})
+ Returns the subclass, to allow usage as a class decorator.
+ """
+ return _abc_register(cls, subclass)
- def __subclasscheck__(cls, subclass):
- """Override for issubclass(subclass, cls)."""
- # Check cache
- if subclass in cls._abc_cache:
- return True
- # Check negative cache; may have to invalidate
- if cls._abc_negative_cache_version < ABCMeta._abc_invalidation_counter:
- # Invalidate the negative cache
- cls._abc_negative_cache = WeakSet()
- cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
- elif subclass in cls._abc_negative_cache:
- return False
- # Check the subclass hook
- ok = cls.__subclasshook__(subclass)
- if ok is not NotImplemented:
- assert isinstance(ok, bool)
- if ok:
- cls._abc_cache.add(subclass)
- else:
- cls._abc_negative_cache.add(subclass)
- return ok
- # Check if it's a direct subclass
- if cls in getattr(subclass, '__mro__', ()):
- cls._abc_cache.add(subclass)
- return True
- # Check if it's a subclass of a registered class (recursive)
- for rcls in cls._abc_registry:
- if issubclass(subclass, rcls):
- cls._abc_cache.add(subclass)
- return True
- # Check if it's a subclass of a subclass (recursive)
- for scls in cls.__subclasses__():
- if issubclass(subclass, scls):
- cls._abc_cache.add(subclass)
- return True
- # No dice; update negative cache
- cls._abc_negative_cache.add(subclass)
- return False
+ def __instancecheck__(cls, instance):
+ """Override for isinstance(instance, cls)."""
+ return _abc_instancecheck(cls, instance)
+
+ def __subclasscheck__(cls, subclass):
+ """Override for issubclass(subclass, cls)."""
+ return _abc_subclasscheck(cls, subclass)
+
+ def _dump_registry(cls, file=None):
+ """Debug helper to print the ABC registry."""
+ print(f"Class: {cls.__module__}.{cls.__qualname__}", file=file)
+ print(f"Inv. counter: {get_cache_token()}", file=file)
+ (_abc_registry, _abc_cache, _abc_negative_cache,
+ _abc_negative_cache_version) = _get_dump(cls)
+ print(f"_abc_registry: {_abc_registry!r}", file=file)
+ print(f"_abc_cache: {_abc_cache!r}", file=file)
+ print(f"_abc_negative_cache: {_abc_negative_cache!r}", file=file)
+ print(f"_abc_negative_cache_version: {_abc_negative_cache_version!r}",
+ file=file)
+
+ def _abc_registry_clear(cls):
+ """Clear the registry (for debugging or testing)."""
+ _reset_registry(cls)
+
+ def _abc_caches_clear(cls):
+ """Clear the caches (for debugging or testing)."""
+ _reset_caches(cls)
class ABC(metaclass=ABCMeta):
@@ -238,13 +168,3 @@
inheritance.
"""
__slots__ = ()
-
-
-def get_cache_token():
- """Returns the current ABC cache token.
-
- The token is an opaque object (supporting equality testing) identifying the
- current version of the ABC cache for virtual subclasses. The token changes
- with every call to ``register()`` on any ABC.
- """
- return ABCMeta._abc_invalidation_counter
diff --git a/Lib/test/libregrtest/refleak.py b/Lib/test/libregrtest/refleak.py
index 2ca9aa8..6724488 100644
--- a/Lib/test/libregrtest/refleak.py
+++ b/Lib/test/libregrtest/refleak.py
@@ -5,6 +5,13 @@
import warnings
from inspect import isabstract
from test import support
+try:
+ from _abc import _get_dump
+except ImportError:
+ def _get_dump(cls):
+ # For legacy Python version
+ return (cls._abc_registry, cls._abc_cache,
+ cls._abc_negative_cache, cls._abc_negative_cache_version)
def dash_R(the_module, test, indirect_test, huntrleaks):
@@ -36,7 +43,7 @@
if not isabstract(abc):
continue
for obj in abc.__subclasses__() + [abc]:
- abcs[obj] = obj._abc_registry.copy()
+ abcs[obj] = _get_dump(obj)[0]
# bpo-31217: Integer pool to get a single integer object for the same
# value. The pool is used to prevent false alarm when checking for memory
@@ -113,7 +120,6 @@
def dash_R_cleanup(fs, ps, pic, zdc, abcs):
import gc, copyreg
import collections.abc
- from weakref import WeakSet
# Restore some original values.
warnings.filters[:] = fs
@@ -137,9 +143,10 @@
abs_classes = filter(isabstract, abs_classes)
for abc in abs_classes:
for obj in abc.__subclasses__() + [abc]:
- obj._abc_registry = abcs.get(obj, WeakSet()).copy()
- obj._abc_cache.clear()
- obj._abc_negative_cache.clear()
+ for ref in abcs.get(obj, set()):
+ if ref() is not None:
+ obj.register(ref())
+ obj._abc_caches_clear()
clear_caches()
diff --git a/Lib/test/test_abc.py b/Lib/test/test_abc.py
index 61c2876..af26c1d 100644
--- a/Lib/test/test_abc.py
+++ b/Lib/test/test_abc.py
@@ -1,422 +1,445 @@
# Copyright 2007 Google, Inc. All Rights Reserved.
# Licensed to PSF under a Contributor Agreement.
+# Note: each test is run with Python and C versions of ABCMeta. Except for
+# test_ABC_helper(), which assures that abc.ABC is an instance of abc.ABCMeta.
+
"""Unit tests for abc.py."""
import unittest
import abc
+import _py_abc
from inspect import isabstract
+def test_factory(abc_ABCMeta, abc_get_cache_token):
+ class TestLegacyAPI(unittest.TestCase):
-class TestLegacyAPI(unittest.TestCase):
-
- def test_abstractproperty_basics(self):
- @abc.abstractproperty
- def foo(self): pass
- self.assertTrue(foo.__isabstractmethod__)
- def bar(self): pass
- self.assertFalse(hasattr(bar, "__isabstractmethod__"))
-
- class C(metaclass=abc.ABCMeta):
+ def test_abstractproperty_basics(self):
@abc.abstractproperty
- def foo(self): return 3
- self.assertRaises(TypeError, C)
- class D(C):
- @property
- def foo(self): return super().foo
- self.assertEqual(D().foo, 3)
- self.assertFalse(getattr(D.foo, "__isabstractmethod__", False))
+ def foo(self): pass
+ self.assertTrue(foo.__isabstractmethod__)
+ def bar(self): pass
+ self.assertFalse(hasattr(bar, "__isabstractmethod__"))
- def test_abstractclassmethod_basics(self):
- @abc.abstractclassmethod
- def foo(cls): pass
- self.assertTrue(foo.__isabstractmethod__)
- @classmethod
- def bar(cls): pass
- self.assertFalse(getattr(bar, "__isabstractmethod__", False))
-
- class C(metaclass=abc.ABCMeta):
- @abc.abstractclassmethod
- def foo(cls): return cls.__name__
- self.assertRaises(TypeError, C)
- class D(C):
- @classmethod
- def foo(cls): return super().foo()
- self.assertEqual(D.foo(), 'D')
- self.assertEqual(D().foo(), 'D')
-
- def test_abstractstaticmethod_basics(self):
- @abc.abstractstaticmethod
- def foo(): pass
- self.assertTrue(foo.__isabstractmethod__)
- @staticmethod
- def bar(): pass
- self.assertFalse(getattr(bar, "__isabstractmethod__", False))
-
- class C(metaclass=abc.ABCMeta):
- @abc.abstractstaticmethod
- def foo(): return 3
- self.assertRaises(TypeError, C)
- class D(C):
- @staticmethod
- def foo(): return 4
- self.assertEqual(D.foo(), 4)
- self.assertEqual(D().foo(), 4)
-
-
-class TestABC(unittest.TestCase):
-
- def test_ABC_helper(self):
- # create an ABC using the helper class and perform basic checks
- class C(abc.ABC):
- @classmethod
- @abc.abstractmethod
- def foo(cls): return cls.__name__
- self.assertEqual(type(C), abc.ABCMeta)
- self.assertRaises(TypeError, C)
- class D(C):
- @classmethod
- def foo(cls): return super().foo()
- self.assertEqual(D.foo(), 'D')
-
- def test_abstractmethod_basics(self):
- @abc.abstractmethod
- def foo(self): pass
- self.assertTrue(foo.__isabstractmethod__)
- def bar(self): pass
- self.assertFalse(hasattr(bar, "__isabstractmethod__"))
-
- def test_abstractproperty_basics(self):
- @property
- @abc.abstractmethod
- def foo(self): pass
- self.assertTrue(foo.__isabstractmethod__)
- def bar(self): pass
- self.assertFalse(getattr(bar, "__isabstractmethod__", False))
-
- class C(metaclass=abc.ABCMeta):
- @property
- @abc.abstractmethod
- def foo(self): return 3
- self.assertRaises(TypeError, C)
- class D(C):
- @C.foo.getter
- def foo(self): return super().foo
- self.assertEqual(D().foo, 3)
-
- def test_abstractclassmethod_basics(self):
- @classmethod
- @abc.abstractmethod
- def foo(cls): pass
- self.assertTrue(foo.__isabstractmethod__)
- @classmethod
- def bar(cls): pass
- self.assertFalse(getattr(bar, "__isabstractmethod__", False))
-
- class C(metaclass=abc.ABCMeta):
- @classmethod
- @abc.abstractmethod
- def foo(cls): return cls.__name__
- self.assertRaises(TypeError, C)
- class D(C):
- @classmethod
- def foo(cls): return super().foo()
- self.assertEqual(D.foo(), 'D')
- self.assertEqual(D().foo(), 'D')
-
- def test_abstractstaticmethod_basics(self):
- @staticmethod
- @abc.abstractmethod
- def foo(): pass
- self.assertTrue(foo.__isabstractmethod__)
- @staticmethod
- def bar(): pass
- self.assertFalse(getattr(bar, "__isabstractmethod__", False))
-
- class C(metaclass=abc.ABCMeta):
- @staticmethod
- @abc.abstractmethod
- def foo(): return 3
- self.assertRaises(TypeError, C)
- class D(C):
- @staticmethod
- def foo(): return 4
- self.assertEqual(D.foo(), 4)
- self.assertEqual(D().foo(), 4)
-
- def test_abstractmethod_integration(self):
- for abstractthing in [abc.abstractmethod, abc.abstractproperty,
- abc.abstractclassmethod,
- abc.abstractstaticmethod]:
- class C(metaclass=abc.ABCMeta):
- @abstractthing
- def foo(self): pass # abstract
- def bar(self): pass # concrete
- self.assertEqual(C.__abstractmethods__, {"foo"})
- self.assertRaises(TypeError, C) # because foo is abstract
- self.assertTrue(isabstract(C))
+ class C(metaclass=abc_ABCMeta):
+ @abc.abstractproperty
+ def foo(self): return 3
+ self.assertRaises(TypeError, C)
class D(C):
- def bar(self): pass # concrete override of concrete
- self.assertEqual(D.__abstractmethods__, {"foo"})
- self.assertRaises(TypeError, D) # because foo is still abstract
- self.assertTrue(isabstract(D))
+ @property
+ def foo(self): return super().foo
+ self.assertEqual(D().foo, 3)
+ self.assertFalse(getattr(D.foo, "__isabstractmethod__", False))
+
+ def test_abstractclassmethod_basics(self):
+ @abc.abstractclassmethod
+ def foo(cls): pass
+ self.assertTrue(foo.__isabstractmethod__)
+ @classmethod
+ def bar(cls): pass
+ self.assertFalse(getattr(bar, "__isabstractmethod__", False))
+
+ class C(metaclass=abc_ABCMeta):
+ @abc.abstractclassmethod
+ def foo(cls): return cls.__name__
+ self.assertRaises(TypeError, C)
+ class D(C):
+ @classmethod
+ def foo(cls): return super().foo()
+ self.assertEqual(D.foo(), 'D')
+ self.assertEqual(D().foo(), 'D')
+
+ def test_abstractstaticmethod_basics(self):
+ @abc.abstractstaticmethod
+ def foo(): pass
+ self.assertTrue(foo.__isabstractmethod__)
+ @staticmethod
+ def bar(): pass
+ self.assertFalse(getattr(bar, "__isabstractmethod__", False))
+
+ class C(metaclass=abc_ABCMeta):
+ @abc.abstractstaticmethod
+ def foo(): return 3
+ self.assertRaises(TypeError, C)
+ class D(C):
+ @staticmethod
+ def foo(): return 4
+ self.assertEqual(D.foo(), 4)
+ self.assertEqual(D().foo(), 4)
+
+
+ class TestABC(unittest.TestCase):
+
+ def test_ABC_helper(self):
+ # create an ABC using the helper class and perform basic checks
+ class C(abc.ABC):
+ @classmethod
+ @abc.abstractmethod
+ def foo(cls): return cls.__name__
+ self.assertEqual(type(C), abc.ABCMeta)
+ self.assertRaises(TypeError, C)
+ class D(C):
+ @classmethod
+ def foo(cls): return super().foo()
+ self.assertEqual(D.foo(), 'D')
+
+ def test_abstractmethod_basics(self):
+ @abc.abstractmethod
+ def foo(self): pass
+ self.assertTrue(foo.__isabstractmethod__)
+ def bar(self): pass
+ self.assertFalse(hasattr(bar, "__isabstractmethod__"))
+
+ def test_abstractproperty_basics(self):
+ @property
+ @abc.abstractmethod
+ def foo(self): pass
+ self.assertTrue(foo.__isabstractmethod__)
+ def bar(self): pass
+ self.assertFalse(getattr(bar, "__isabstractmethod__", False))
+
+ class C(metaclass=abc_ABCMeta):
+ @property
+ @abc.abstractmethod
+ def foo(self): return 3
+ self.assertRaises(TypeError, C)
+ class D(C):
+ @C.foo.getter
+ def foo(self): return super().foo
+ self.assertEqual(D().foo, 3)
+
+ def test_abstractclassmethod_basics(self):
+ @classmethod
+ @abc.abstractmethod
+ def foo(cls): pass
+ self.assertTrue(foo.__isabstractmethod__)
+ @classmethod
+ def bar(cls): pass
+ self.assertFalse(getattr(bar, "__isabstractmethod__", False))
+
+ class C(metaclass=abc_ABCMeta):
+ @classmethod
+ @abc.abstractmethod
+ def foo(cls): return cls.__name__
+ self.assertRaises(TypeError, C)
+ class D(C):
+ @classmethod
+ def foo(cls): return super().foo()
+ self.assertEqual(D.foo(), 'D')
+ self.assertEqual(D().foo(), 'D')
+
+ def test_abstractstaticmethod_basics(self):
+ @staticmethod
+ @abc.abstractmethod
+ def foo(): pass
+ self.assertTrue(foo.__isabstractmethod__)
+ @staticmethod
+ def bar(): pass
+ self.assertFalse(getattr(bar, "__isabstractmethod__", False))
+
+ class C(metaclass=abc_ABCMeta):
+ @staticmethod
+ @abc.abstractmethod
+ def foo(): return 3
+ self.assertRaises(TypeError, C)
+ class D(C):
+ @staticmethod
+ def foo(): return 4
+ self.assertEqual(D.foo(), 4)
+ self.assertEqual(D().foo(), 4)
+
+ def test_abstractmethod_integration(self):
+ for abstractthing in [abc.abstractmethod, abc.abstractproperty,
+ abc.abstractclassmethod,
+ abc.abstractstaticmethod]:
+ class C(metaclass=abc_ABCMeta):
+ @abstractthing
+ def foo(self): pass # abstract
+ def bar(self): pass # concrete
+ self.assertEqual(C.__abstractmethods__, {"foo"})
+ self.assertRaises(TypeError, C) # because foo is abstract
+ self.assertTrue(isabstract(C))
+ class D(C):
+ def bar(self): pass # concrete override of concrete
+ self.assertEqual(D.__abstractmethods__, {"foo"})
+ self.assertRaises(TypeError, D) # because foo is still abstract
+ self.assertTrue(isabstract(D))
+ class E(D):
+ def foo(self): pass
+ self.assertEqual(E.__abstractmethods__, set())
+ E() # now foo is concrete, too
+ self.assertFalse(isabstract(E))
+ class F(E):
+ @abstractthing
+ def bar(self): pass # abstract override of concrete
+ self.assertEqual(F.__abstractmethods__, {"bar"})
+ self.assertRaises(TypeError, F) # because bar is abstract now
+ self.assertTrue(isabstract(F))
+
+ def test_descriptors_with_abstractmethod(self):
+ class C(metaclass=abc_ABCMeta):
+ @property
+ @abc.abstractmethod
+ def foo(self): return 3
+ @foo.setter
+ @abc.abstractmethod
+ def foo(self, val): pass
+ self.assertRaises(TypeError, C)
+ class D(C):
+ @C.foo.getter
+ def foo(self): return super().foo
+ self.assertRaises(TypeError, D)
class E(D):
- def foo(self): pass
- self.assertEqual(E.__abstractmethods__, set())
- E() # now foo is concrete, too
- self.assertFalse(isabstract(E))
- class F(E):
- @abstractthing
- def bar(self): pass # abstract override of concrete
- self.assertEqual(F.__abstractmethods__, {"bar"})
- self.assertRaises(TypeError, F) # because bar is abstract now
- self.assertTrue(isabstract(F))
+ @D.foo.setter
+ def foo(self, val): pass
+ self.assertEqual(E().foo, 3)
+ # check that the property's __isabstractmethod__ descriptor does the
+ # right thing when presented with a value that fails truth testing:
+ class NotBool(object):
+ def __bool__(self):
+ raise ValueError()
+ __len__ = __bool__
+ with self.assertRaises(ValueError):
+ class F(C):
+ def bar(self):
+ pass
+ bar.__isabstractmethod__ = NotBool()
+ foo = property(bar)
- def test_descriptors_with_abstractmethod(self):
- class C(metaclass=abc.ABCMeta):
- @property
- @abc.abstractmethod
- def foo(self): return 3
- @foo.setter
- @abc.abstractmethod
- def foo(self, val): pass
- self.assertRaises(TypeError, C)
- class D(C):
- @C.foo.getter
- def foo(self): return super().foo
- self.assertRaises(TypeError, D)
- class E(D):
- @D.foo.setter
- def foo(self, val): pass
- self.assertEqual(E().foo, 3)
- # check that the property's __isabstractmethod__ descriptor does the
- # right thing when presented with a value that fails truth testing:
- class NotBool(object):
- def __bool__(self):
- raise ValueError()
- __len__ = __bool__
- with self.assertRaises(ValueError):
- class F(C):
- def bar(self):
+
+ def test_customdescriptors_with_abstractmethod(self):
+ class Descriptor:
+ def __init__(self, fget, fset=None):
+ self._fget = fget
+ self._fset = fset
+ def getter(self, callable):
+ return Descriptor(callable, self._fget)
+ def setter(self, callable):
+ return Descriptor(self._fget, callable)
+ @property
+ def __isabstractmethod__(self):
+ return (getattr(self._fget, '__isabstractmethod__', False)
+ or getattr(self._fset, '__isabstractmethod__', False))
+ class C(metaclass=abc_ABCMeta):
+ @Descriptor
+ @abc.abstractmethod
+ def foo(self): return 3
+ @foo.setter
+ @abc.abstractmethod
+ def foo(self, val): pass
+ self.assertRaises(TypeError, C)
+ class D(C):
+ @C.foo.getter
+ def foo(self): return super().foo
+ self.assertRaises(TypeError, D)
+ class E(D):
+ @D.foo.setter
+ def foo(self, val): pass
+ self.assertFalse(E.foo.__isabstractmethod__)
+
+ def test_metaclass_abc(self):
+ # Metaclasses can be ABCs, too.
+ class A(metaclass=abc_ABCMeta):
+ @abc.abstractmethod
+ def x(self):
pass
- bar.__isabstractmethod__ = NotBool()
- foo = property(bar)
-
-
- def test_customdescriptors_with_abstractmethod(self):
- class Descriptor:
- def __init__(self, fget, fset=None):
- self._fget = fget
- self._fset = fset
- def getter(self, callable):
- return Descriptor(callable, self._fget)
- def setter(self, callable):
- return Descriptor(self._fget, callable)
- @property
- def __isabstractmethod__(self):
- return (getattr(self._fget, '__isabstractmethod__', False)
- or getattr(self._fset, '__isabstractmethod__', False))
- class C(metaclass=abc.ABCMeta):
- @Descriptor
- @abc.abstractmethod
- def foo(self): return 3
- @foo.setter
- @abc.abstractmethod
- def foo(self, val): pass
- self.assertRaises(TypeError, C)
- class D(C):
- @C.foo.getter
- def foo(self): return super().foo
- self.assertRaises(TypeError, D)
- class E(D):
- @D.foo.setter
- def foo(self, val): pass
- self.assertFalse(E.foo.__isabstractmethod__)
-
- def test_metaclass_abc(self):
- # Metaclasses can be ABCs, too.
- class A(metaclass=abc.ABCMeta):
- @abc.abstractmethod
- def x(self):
+ self.assertEqual(A.__abstractmethods__, {"x"})
+ class meta(type, A):
+ def x(self):
+ return 1
+ class C(metaclass=meta):
pass
- self.assertEqual(A.__abstractmethods__, {"x"})
- class meta(type, A):
- def x(self):
- return 1
- class C(metaclass=meta):
- pass
- def test_registration_basics(self):
- class A(metaclass=abc.ABCMeta):
- pass
- class B(object):
- pass
- b = B()
- self.assertFalse(issubclass(B, A))
- self.assertFalse(issubclass(B, (A,)))
- self.assertNotIsInstance(b, A)
- self.assertNotIsInstance(b, (A,))
- B1 = A.register(B)
- self.assertTrue(issubclass(B, A))
- self.assertTrue(issubclass(B, (A,)))
- self.assertIsInstance(b, A)
- self.assertIsInstance(b, (A,))
- self.assertIs(B1, B)
- class C(B):
- pass
- c = C()
- self.assertTrue(issubclass(C, A))
- self.assertTrue(issubclass(C, (A,)))
- self.assertIsInstance(c, A)
- self.assertIsInstance(c, (A,))
+ def test_registration_basics(self):
+ class A(metaclass=abc_ABCMeta):
+ pass
+ class B(object):
+ pass
+ b = B()
+ self.assertFalse(issubclass(B, A))
+ self.assertFalse(issubclass(B, (A,)))
+ self.assertNotIsInstance(b, A)
+ self.assertNotIsInstance(b, (A,))
+ B1 = A.register(B)
+ self.assertTrue(issubclass(B, A))
+ self.assertTrue(issubclass(B, (A,)))
+ self.assertIsInstance(b, A)
+ self.assertIsInstance(b, (A,))
+ self.assertIs(B1, B)
+ class C(B):
+ pass
+ c = C()
+ self.assertTrue(issubclass(C, A))
+ self.assertTrue(issubclass(C, (A,)))
+ self.assertIsInstance(c, A)
+ self.assertIsInstance(c, (A,))
- def test_register_as_class_deco(self):
- class A(metaclass=abc.ABCMeta):
- pass
- @A.register
- class B(object):
- pass
- b = B()
- self.assertTrue(issubclass(B, A))
- self.assertTrue(issubclass(B, (A,)))
- self.assertIsInstance(b, A)
- self.assertIsInstance(b, (A,))
- @A.register
- class C(B):
- pass
- c = C()
- self.assertTrue(issubclass(C, A))
- self.assertTrue(issubclass(C, (A,)))
- self.assertIsInstance(c, A)
- self.assertIsInstance(c, (A,))
- self.assertIs(C, A.register(C))
+ def test_register_as_class_deco(self):
+ class A(metaclass=abc_ABCMeta):
+ pass
+ @A.register
+ class B(object):
+ pass
+ b = B()
+ self.assertTrue(issubclass(B, A))
+ self.assertTrue(issubclass(B, (A,)))
+ self.assertIsInstance(b, A)
+ self.assertIsInstance(b, (A,))
+ @A.register
+ class C(B):
+ pass
+ c = C()
+ self.assertTrue(issubclass(C, A))
+ self.assertTrue(issubclass(C, (A,)))
+ self.assertIsInstance(c, A)
+ self.assertIsInstance(c, (A,))
+ self.assertIs(C, A.register(C))
- def test_isinstance_invalidation(self):
- class A(metaclass=abc.ABCMeta):
- pass
- class B:
- pass
- b = B()
- self.assertFalse(isinstance(b, A))
- self.assertFalse(isinstance(b, (A,)))
- token_old = abc.get_cache_token()
- A.register(B)
- token_new = abc.get_cache_token()
- self.assertNotEqual(token_old, token_new)
- self.assertTrue(isinstance(b, A))
- self.assertTrue(isinstance(b, (A,)))
+ def test_isinstance_invalidation(self):
+ class A(metaclass=abc_ABCMeta):
+ pass
+ class B:
+ pass
+ b = B()
+ self.assertFalse(isinstance(b, A))
+ self.assertFalse(isinstance(b, (A,)))
+ token_old = abc_get_cache_token()
+ A.register(B)
+ token_new = abc_get_cache_token()
+ self.assertNotEqual(token_old, token_new)
+ self.assertTrue(isinstance(b, A))
+ self.assertTrue(isinstance(b, (A,)))
- def test_registration_builtins(self):
- class A(metaclass=abc.ABCMeta):
- pass
- A.register(int)
- self.assertIsInstance(42, A)
- self.assertIsInstance(42, (A,))
- self.assertTrue(issubclass(int, A))
- self.assertTrue(issubclass(int, (A,)))
- class B(A):
- pass
- B.register(str)
- class C(str): pass
- self.assertIsInstance("", A)
- self.assertIsInstance("", (A,))
- self.assertTrue(issubclass(str, A))
- self.assertTrue(issubclass(str, (A,)))
- self.assertTrue(issubclass(C, A))
- self.assertTrue(issubclass(C, (A,)))
+ def test_registration_builtins(self):
+ class A(metaclass=abc_ABCMeta):
+ pass
+ A.register(int)
+ self.assertIsInstance(42, A)
+ self.assertIsInstance(42, (A,))
+ self.assertTrue(issubclass(int, A))
+ self.assertTrue(issubclass(int, (A,)))
+ class B(A):
+ pass
+ B.register(str)
+ class C(str): pass
+ self.assertIsInstance("", A)
+ self.assertIsInstance("", (A,))
+ self.assertTrue(issubclass(str, A))
+ self.assertTrue(issubclass(str, (A,)))
+ self.assertTrue(issubclass(C, A))
+ self.assertTrue(issubclass(C, (A,)))
- def test_registration_edge_cases(self):
- class A(metaclass=abc.ABCMeta):
- pass
- A.register(A) # should pass silently
- class A1(A):
- pass
- self.assertRaises(RuntimeError, A1.register, A) # cycles not allowed
- class B(object):
- pass
- A1.register(B) # ok
- A1.register(B) # should pass silently
- class C(A):
- pass
- A.register(C) # should pass silently
- self.assertRaises(RuntimeError, C.register, A) # cycles not allowed
- C.register(B) # ok
+ def test_registration_edge_cases(self):
+ class A(metaclass=abc_ABCMeta):
+ pass
+ A.register(A) # should pass silently
+ class A1(A):
+ pass
+ self.assertRaises(RuntimeError, A1.register, A) # cycles not allowed
+ class B(object):
+ pass
+ A1.register(B) # ok
+ A1.register(B) # should pass silently
+ class C(A):
+ pass
+ A.register(C) # should pass silently
+ self.assertRaises(RuntimeError, C.register, A) # cycles not allowed
+ C.register(B) # ok
- def test_register_non_class(self):
- class A(metaclass=abc.ABCMeta):
- pass
- self.assertRaisesRegex(TypeError, "Can only register classes",
- A.register, 4)
+ def test_register_non_class(self):
+ class A(metaclass=abc_ABCMeta):
+ pass
+ self.assertRaisesRegex(TypeError, "Can only register classes",
+ A.register, 4)
- def test_registration_transitiveness(self):
- class A(metaclass=abc.ABCMeta):
- pass
- self.assertTrue(issubclass(A, A))
- self.assertTrue(issubclass(A, (A,)))
- class B(metaclass=abc.ABCMeta):
- pass
- self.assertFalse(issubclass(A, B))
- self.assertFalse(issubclass(A, (B,)))
- self.assertFalse(issubclass(B, A))
- self.assertFalse(issubclass(B, (A,)))
- class C(metaclass=abc.ABCMeta):
- pass
- A.register(B)
- class B1(B):
- pass
- self.assertTrue(issubclass(B1, A))
- self.assertTrue(issubclass(B1, (A,)))
- class C1(C):
- pass
- B1.register(C1)
- self.assertFalse(issubclass(C, B))
- self.assertFalse(issubclass(C, (B,)))
- self.assertFalse(issubclass(C, B1))
- self.assertFalse(issubclass(C, (B1,)))
- self.assertTrue(issubclass(C1, A))
- self.assertTrue(issubclass(C1, (A,)))
- self.assertTrue(issubclass(C1, B))
- self.assertTrue(issubclass(C1, (B,)))
- self.assertTrue(issubclass(C1, B1))
- self.assertTrue(issubclass(C1, (B1,)))
- C1.register(int)
- class MyInt(int):
- pass
- self.assertTrue(issubclass(MyInt, A))
- self.assertTrue(issubclass(MyInt, (A,)))
- self.assertIsInstance(42, A)
- self.assertIsInstance(42, (A,))
+ def test_registration_transitiveness(self):
+ class A(metaclass=abc_ABCMeta):
+ pass
+ self.assertTrue(issubclass(A, A))
+ self.assertTrue(issubclass(A, (A,)))
+ class B(metaclass=abc_ABCMeta):
+ pass
+ self.assertFalse(issubclass(A, B))
+ self.assertFalse(issubclass(A, (B,)))
+ self.assertFalse(issubclass(B, A))
+ self.assertFalse(issubclass(B, (A,)))
+ class C(metaclass=abc_ABCMeta):
+ pass
+ A.register(B)
+ class B1(B):
+ pass
+ self.assertTrue(issubclass(B1, A))
+ self.assertTrue(issubclass(B1, (A,)))
+ class C1(C):
+ pass
+ B1.register(C1)
+ self.assertFalse(issubclass(C, B))
+ self.assertFalse(issubclass(C, (B,)))
+ self.assertFalse(issubclass(C, B1))
+ self.assertFalse(issubclass(C, (B1,)))
+ self.assertTrue(issubclass(C1, A))
+ self.assertTrue(issubclass(C1, (A,)))
+ self.assertTrue(issubclass(C1, B))
+ self.assertTrue(issubclass(C1, (B,)))
+ self.assertTrue(issubclass(C1, B1))
+ self.assertTrue(issubclass(C1, (B1,)))
+ C1.register(int)
+ class MyInt(int):
+ pass
+ self.assertTrue(issubclass(MyInt, A))
+ self.assertTrue(issubclass(MyInt, (A,)))
+ self.assertIsInstance(42, A)
+ self.assertIsInstance(42, (A,))
- def test_all_new_methods_are_called(self):
- class A(metaclass=abc.ABCMeta):
- pass
- class B(object):
- counter = 0
- def __new__(cls):
- B.counter += 1
- return super().__new__(cls)
- class C(A, B):
- pass
- self.assertEqual(B.counter, 0)
- C()
- self.assertEqual(B.counter, 1)
+ def test_all_new_methods_are_called(self):
+ class A(metaclass=abc_ABCMeta):
+ pass
+ class B(object):
+ counter = 0
+ def __new__(cls):
+ B.counter += 1
+ return super().__new__(cls)
+ class C(A, B):
+ pass
+ self.assertEqual(B.counter, 0)
+ C()
+ self.assertEqual(B.counter, 1)
- def test_ABC_has___slots__(self):
- self.assertTrue(hasattr(abc.ABC, '__slots__'))
+ def test_ABC_has___slots__(self):
+ self.assertTrue(hasattr(abc.ABC, '__slots__'))
+
+ def test_tricky_new_works(self):
+ def with_metaclass(meta, *bases):
+ class metaclass(type):
+ def __new__(cls, name, this_bases, d):
+ return meta(name, bases, d)
+ return type.__new__(metaclass, 'temporary_class', (), {})
+ class A: ...
+ class B: ...
+ class C(with_metaclass(abc_ABCMeta, A, B)):
+ pass
+ self.assertEqual(C.__class__, abc_ABCMeta)
-class TestABCWithInitSubclass(unittest.TestCase):
- def test_works_with_init_subclass(self):
- saved_kwargs = {}
- class ReceivesClassKwargs:
- def __init_subclass__(cls, **kwargs):
- super().__init_subclass__()
- saved_kwargs.update(kwargs)
- class Receiver(ReceivesClassKwargs, abc.ABC, x=1, y=2, z=3):
- pass
- self.assertEqual(saved_kwargs, dict(x=1, y=2, z=3))
+ class TestABCWithInitSubclass(unittest.TestCase):
+ def test_works_with_init_subclass(self):
+ class abc_ABC(metaclass=abc_ABCMeta):
+ __slots__ = ()
+ saved_kwargs = {}
+ class ReceivesClassKwargs:
+ def __init_subclass__(cls, **kwargs):
+ super().__init_subclass__()
+ saved_kwargs.update(kwargs)
+ class Receiver(ReceivesClassKwargs, abc_ABC, x=1, y=2, z=3):
+ pass
+ self.assertEqual(saved_kwargs, dict(x=1, y=2, z=3))
+ return TestLegacyAPI, TestABC, TestABCWithInitSubclass
+TestLegacyAPI_Py, TestABC_Py, TestABCWithInitSubclass_Py = test_factory(abc.ABCMeta,
+ abc.get_cache_token)
+TestLegacyAPI_C, TestABC_C, TestABCWithInitSubclass_C = test_factory(_py_abc.ABCMeta,
+ _py_abc.get_cache_token)
if __name__ == "__main__":
unittest.main()
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index 3f24faf..f56caa1 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -761,8 +761,8 @@
self.assertIsInstance(1, C)
C[int]
self.assertIsInstance(1, C)
- C._abc_registry.clear()
- C._abc_cache.clear() # To keep refleak hunting mode clean
+ C._abc_registry_clear()
+ C._abc_caches_clear() # To keep refleak hunting mode clean
def test_false_subclasses(self):
class MyMapping(MutableMapping[str, str]): pass